Beware: ti hardware and 3T stems

Just a word of caution: I was putting on a new 3T ARX Team stem and the heads on two ti bolts snapped off well before the torque wrench reached 5nm. I'm glad that didn't occur while riding. The ease at which the heads snapped scared the cr@p out of me. I replaced those ti parts with steel ones from a 3T ARX Pro stem. I had only bought the stem for the color and didn't realize the bolts were titanium until I checked the package listing.

I did a quick Google search and read that it has happened to others with 3T stems - cheap ti hardware. I'm going to replace the hardware on my other ARX Team stem with stainless steel bolts.

Just wanted to give folks a heads up and note that it's best to keep your weight weenie-ness in check.

My Bikes
"It's supposed to be hard...The hard is what makes it great."

Proper torque specs are usually based on the strength of the hardware, which in turn is matched to the application by the company who makes the product.

Changing the material of the hardware requires an adjustment in tightening torque to prevent failure like the OPs. But that may lead to inadequate holding power on the clamp. To properly substitute Ti hardware for steel, you'd have to use a larger bolt to maintain the same strength. That would mean re-engineering the part completely.

Proper torque specs are usually based on the strength of the hardware, which in turn is matched to the application by the company who makes the product.

Changing the material of the hardware requires an adjustment in tightening torque to prevent failure like the OPs. But that may lead to inadequate holding power on the clamp. To properly substitute Ti hardware for steel, you'd have to use a larger bolt to maintain the same strength. That would mean re-engineering the part completely.

Not really, those torque specs exist to avoid snapping the handlebar, not damaging the stem. If you look carefully, the same torque spec range is given for all stems and in all different materials used bar a few exceptions : between 4.5 to 6nm.

A bolt failing is not a big problem. At least less than snapping the handlebars. That's the reason they sell stems with buttery aluminium or titanium bolts : it avoids people overtorquing them.

As you point out, the torque spec starts with the engineers determining the target clamping force,.

Then the suitable hardware is chosen. Since we're in a weight driven industry, that hardware is generally selected to be the lightest (weakest) hardware adequate to the task. This is also good engineering practice, because screw fasteners are least likely to vibrate loose if they're elongated slightly when tightened to spec,. Another benefit to not using overly strong screws is that act sort of like a fuse, breaking if over torqued before the more expensive parts they're holding.

Once the right hardware is selected the tension needed to achieve the desired clamping force is translated to a torque value based on the thread's helix angle, and allowing for thread friction. That's the final torque.

But it's at the end of a chain of calculations, and changing any of the elements in that chain changes things entirely.

It's no big deal if a screw breaks while being tightened, unless it breaks flush in an expensive part. But it could be a big deal if hardware of insufficient strength is substituted and used in any assembly and breaks in use. Ask anyone who works on aircraft about how serious they are about using the EXACT spec. screws, and their concerns about the issue of counterfeit screws that don't match the spec. they're marked as.

So you're right, torque isn't about the screw, it's about the clamp, but since it's the screw that provides that clamping force it's about the screw after all.

Not really, those torque specs exist to avoid snapping the handlebar, not damaging the stem.

You misunderstand the concept of torque, which is a unit of rotational force. With fasteners, torque is used to indicate to which point a fastener should be tightened, i.e., how much it should be stretched.

Stems put a clamping force on a handlebar, not torque. The stem manufacturer generally doesn't know and would never hazard a guess as to what a safe clamping force would be for a particular handlebar.

Not really, those torque specs exist to avoid snapping the handlebar, not damaging the stem. If you look carefully, the same torque spec range is given for all stems and in all different materials used bar a few exceptions : between 4.5 to 6nm.

A bolt failing is not a big problem. At least less than snapping the handlebars. That's the reason they sell stems with buttery aluminium or titanium bolts : it avoids people overtorquing them.

FWIW, I have a 3T stem with Ti screws. I've heard this warning before and been concerned as I remove and reinstall my bars on occasion for airline travel. I always use a Ritchey 5nm torque key or a click type torque wrench and have not yet had a problem. I have had FSA stems with Ti screws and had no issues with them either. I guess it's possible that 3T has a batch of defective screws out there. It may not make any difference but I do take care to tighten the screws incrementally. I do use Ti-prep on the threads.

OP, did you happen to lubricate the threads with either grease or anti-sieze? Either of those could cause a joint to be over-torqued.

This misses the point, and is one of the reasons, I'm not a fan of mindlessly using a torque wrench and following a spec without knowing the implications.

Generally all torque specs for screw fasteners are "wet" meaning correct for lubricated threads. This is because it's standard practice to lubricate a thread. If a spec is for dry threads, it's incumbent on the published spec. to make that clear.

The OPs breakage of a Ti screw is predictable. The assembly called for a screw of a given strength. He substituted a same size screw of weaker material, resulting in a screw of significantly less strength, and it (predictably) failed. Fortunately it failed on assembly and not while riding.

By analogy, If you were lifting an elevator with 2 1/2" steel cables, would you feel safe using only one, or maybe 2 1/2" cotton ropes?

Stems usually require narrow head bolts, which is not an ideal application for Ti. That being said, a lot of my Ritchey stems came with Ti bolts and I haven't snapped any of them yet.

“Bicycling has done more to emancipate women than anything else in the world.” - Susan B. Anthony 1896
"Cycling and ethical bankruptcy have always gone together." - Bike Snob NYC
"White personifies this generation's obsession with superficiality, one in which a carefully curated social media post is more important than the actual ride" - Daimeon Shanks
"I haven't %^&* like that since I was an altar boy" Hank Moody

This misses the point, and is one of the reasons, I'm not a fan of mindlessly using a torque wrench and following a spec without knowing the implications.

Generally all torque specs for screw fasteners are "wet" meaning correct for lubricated threads. This is because it's standard practice to lubricate a thread. If a spec is for dry threads, it's incumbent on the published spec. to make that clear.

The OPs breakage of a Ti screw is predictable. The assembly called for a screw of a given strength. He substituted a same size screw of weaker material, resulting in a screw of significantly less strength, and it (predictably) failed. Fortunately it failed on assembly and not while riding.

By analogy, If you were lifting an elevator with 2 1/2" steel cables, would you feel safe using only one, or maybe 2 1/2" cotton ropes?

The hardware is the original with the stem, not a substitute (by me). 3T uses ti bolts on the ARX Team stems vs steel in the ARX Pro. The bolts are exactly the same size and length, and they come with anti-seize prep.

My concern was that the heads snapped off well before they were fully tightened (to torque spec). Being a force/weight bearing contact point and more importantly on a control function, it almost seems to be negligent on 3T's part.

I figured it was worth warning others from a potentially catastrophic event.

My Bikes
"It's supposed to be hard...The hard is what makes it great."

Not lubricating the bolts/threads seems like a really bad idea considering the Ti is going into Aluminum. I use anti-seize on all Ti bolts to avoid galling.

“Bicycling has done more to emancipate women than anything else in the world.” - Susan B. Anthony 1896
"Cycling and ethical bankruptcy have always gone together." - Bike Snob NYC
"White personifies this generation's obsession with superficiality, one in which a carefully curated social media post is more important than the actual ride" - Daimeon Shanks
"I haven't %^&* like that since I was an altar boy" Hank Moody

The hardware is the original with the stem, not a substitute (by me). 3T uses ti bolts on the ARX Team stems vs steel in the ARX Pro. The bolts are exactly the same size and length, and they come with anti-seize prep.

My concern was that the heads snapped off well before they were fully tightened (to torque spec). Being a force/weight bearing contact point and more importantly on a control function, it almost seems to be negligent on 3T's part.

That's a horse of a different color. I'm curious, does 3t publish a different torque spec for the steel and Ti hardware?. On the one hand if the spec is low enough for Ti to be OK, then it's OK for both, but if the spec was designed around steel hardware, than Ti might be inadequate to the task.

As I said, I'm not a fan of blindly following torque specs, partly because I don't trust the sources. I've spoken to too many professional mechanics who've found, like you, some parts break below the max torque, and others won't hold properly unless you exceed max torque.

When assembling things like posts or stems I always try to use the minimum tightness that does the job (with a reserve). On superlight stuff, I use my lapping compound trick to improve the hold and lower the needed clamping force to buy myself a bigger margin of safety.

Generally all torque specs for screw fasteners are "wet" meaning correct for lubricated threads. This is because it's standard practice to lubricate a thread. If a spec is for dry threads, it's incumbent on the published spec. to make that clear.

If you switch out your 'wet' and 'dry' terms in that statement, you will end up being correct. Sorry, but standard industrial torque specs are dry. If they are given for lubricated threads, then the lubricant is specified.

Who knows what bicycle manufacturers provide though, since they never state one or the other. Often it just doesn't matter because there are so many other variables....fastener material, thread quality, fastener coating, surface finish between the fastener and whatever it's threading into, etc.

It maybe cheap Ti bolts.. Torque specs is good and all but I think ensuring all loads and torque are distributed evenly is the key.
I found smearing some grease on the back of the bolthead helps all the bolts turn evenly. I also use a thin hex key or anything with a even thickness to check the gap all around the face plate before I start.

One problem I have ran into when the face plate was not evenly distributed, this means the bolt heads dig into the plate at an angle and it will either sheer the plate or the bolt. Yes, speaking from experience.

Perhaps, perhaps not. But none of that alters the fact that if you have two bolts of the same diameter with one made of Ti and the other made of steel, the Ti bolt will be the significantly weaker one. As FBinNY pointed out, if you substitute a Ti bolt for a for steel bolt, you need to spec a larger-diameter bolt and redesign the component to accept that larger-diameter bolt. Hardly anyone in the bike business does that, so Ti bike stuff simply breaks easier than steel bike stuff.

...Sorry, but standard industrial torque specs are dry. If they are given for lubricated threads, then the lubricant is specified.

This is true in my experience in motorcycles, aircraft and other manufacturing situations. In the case of stems, Ritchey calls out for "greasing the threads" in their stem manual and FSA calls out for using "Ti-Prep". 3T offers no such instruction, though the torque spec and screw sizes, and general screw materials are the same as for FSA and Ritchey stems.

I popped a 3T ARX Team ti bolt as well. Only replaced the steerer bolts with steel as it's what I've got on hand and that's where it happened. Handlebar clamp section was never a problem, probably because clamping torque is distributed among 4 bolts as opposed to 2.

On the otherhand, I never popped a Zipp SC SL Ti bolt, which uses a torx head. Instead, I'm nearly stripping the head.

I purchased a 3t stem with ti bolts new online. Installed with a Spin Doctor click type torque wrench to spec and a bolt snapped. There are a lot of variables here. Defective screw? Wrong torque specs.? Defective torque wrench? Error somehow on my part?

The bolts are fragile that we know. 3t basically told me to pound sand and the online retailer decided to make me jump through hoops with shipping the stem and still no guarantee they would warranty it. I just asked them to ship me 1 bolt and they declined.

It maybe cheap Ti bolts.. Torque specs is good and all but I think ensuring all loads and torque are distributed evenly is the key.
I found smearing some grease on the back of the bolthead helps all the bolts turn evenly. I also use a thin hex key or anything with a even thickness to check the gap all around the face plate before I start.

One problem I have ran into when the face plate was not evenly distributed, this means the bolt heads dig into the plate at an angle and it will either sheer the plate or the bolt. Yes, speaking from experience.

Just to add another detail, I did distribute the force evenly by making 1 to 1.5 turns on each bolt and moving in a cross pattern, like you would tightening lug nuts on an auto wheel.

My Bikes
"It's supposed to be hard...The hard is what makes it great."